This assay essentially determines a preference between a comparatively safe and comofrtable environment (the closed arms ) and a risky enviornment (elevated open spaces). The general principle is that the more “anxious” the subjects are, the less likely they will be to explore a risky or threatening envionment. The EPM has been validated pharmacologically, ethologically and with other tests of anxiety-like behaviors and physiologically [1-31]. The animal is generally placed in one of the closed arms to start. The number of entries into each portion of the EPM (open and closed) are scored in addition to the total time spent in each portion.

26. Schmitt, U. and C. Hiemke, Combination of open field and elevated plus-maze: A suitable test battery to assess strain as well as treatment differences in rat behavior. Progress in Neuro-Psychopharmacology and Biological Psychiatry, 1998. 22(7): p. 1197.

27. Tambour, S., et al., Dissociation between the locomotor and anxiolytic effects of acetaldehyde in the elevated plus-maze: Evidence that acetaldehyde is not involved in the anxiolytic effects of ethanol in mice. Eur Neuropsychopharmacol, 2005.